The present invention relates to an apparatus for patterning a cylindrical surface, and specifically to an apparatus for patterning a die or a mill.
A conventional apparatus for patterning a cylindrical surface of a die or a mill is shown in FIG. 1 and indicated generally by the numeral 10. Conventional patterning apparatus 10 includes a punch 12 which is held by a punch holder 14 attached to a holder arm 16. The middle of holder arm 16 is pivotally connected to an arm support member 18 (partially obscured in FIG. 1.) so as to permit punch 12 to be moved up and down in a single plane. Arm support member 18 is fixedly attached to a traveling support member 20 which slidably rests atop a machine base 22. A vertical punch stop 24 is attached to arm support member 18 and can be adjusted to limit the vertical movement of arm 16.
Punch 12 comprises a tool for marking a blank cylinder 26 to be patterned into a die or a mill, as desired. The size and shape of punch 12 varies according to the pattern desired to be produced on blank cylinder 26, which has a journal 25 integrally formed on each end thereof. Each journal 25 is mounted rotatably on a center as known in the art, with one journal (not shown) held by a dog (not shown).
In operation, a human operator manually raises holder 14 until arm 16 contacts stop 24. The operator then releases holder 14 and permits punch 12 to strike the surface of blank cylinder 26, thereby imprinting a mark into the surface of blank cylinder 26. The operator may then inspect the mark so formed and accordingly may repeat the procedure several times until the desired depth is obtained in the surface of cylinder 26. The position of stop 24 also affects the depth of the mark, since this position determines the height from which punch 12 is released.
Each mark so formed in the surface of cylinder 26 constitutes only one small portion of the overall pattern to be formed in the surface of cylinder 26. The overall pattern is produced by exposing different sections of the surface of blank cylinder 26 to the strike of punch 12. In conventional apparatus 10, one center is supported by a center support member 29. The dog (not shown) holding the other journal is connected to the central axis of a first metering disc 30. The circumference of metering disc 30 has a plurality of teeth 32. Each tooth 32 is spaced equidistantly from the next adjacent tooth 32 around the circumference of disc 30. Because of the direct connection between disc 30 and the obscured dog, a single revolution of disc 30 causes a single revolution of this dog and accordingly blank cylinder 26 held thereby. Rotational movement of the surface of cylinder 26 can be very precisely controlled by rotation of disc 30 because of the disparity in diameter between cylinder 26 and disc 30.
In operation, the human operator determines how far the surface of cylinder 26 must be rotated to expose the desired portion of the blank surface to receive the next strike of punch 12 required to form the next section of the overall pattern being produced on the surface of cylinder 26. Then the operator calculates the corresponding rotation of disc 30 in terms of the number of teeth 32 through which disc 30 must be rotated. A first shifting arm 34 pivots at one end about the axis of disc 30 and has a handle 36 at the opposite end thereof. A ratchet pawl (not shown) is attached to arm 34 near handle 36 and engages teeth 32 of disc 30. The operator lifts handle 36 until the pawl ratchets over the desired number of teeth 32. Then the operator brings the handle back down until arm 34 engages a lower arm stop 38, which can be adjusted to stop arm 34 at different heights. Disc 30 rotates in conjunction with the downward stroke of handle 36, and accordingly, the surface of cylinder 26 moves the desired distance relative to punch 12 that is required for receiving the imprint of the next punch strike. This procedure can be followed until punch 12 has marked a complete circumferential portion around the surface of cylinder 26. Moreover, an upper arm stop, such as bolt and nut combination 40, can be attached to a first arm gauge 41, which is secured to machine base 22 between first shifting arm 34 and first shifting disc 30. Bolt and nut combination 40 can be set at a point at which arm 34 will have moved a sufficient distance to reach the desired tooth of disc 30.
The operator must perform another operation with conventional apparatus 10 in order to move punch 12 along the longitudinal axis of cylinder 26 in preparation for striking another series of marks around a different circumferential portion of the cylinder surface. As described above, holder arm 16 is pivotally attached to arm support member 18 which is fixed to travelling support member 20. The upper surface of machine base 22 slidably supports travelling support member 20. In addition, machine base 22 has a rectangular opening 42 extending from one end thereof to that portion of machine base 22 which supports metering disc 30. Travelling support member 20 has a rectangular tongue portion (not shown) which slidably fits between the sides of rectangular opening 42. A threaded worm gear receptacle (not shown) extends through the tongue portion of travelling support member 20. One end of a threaded worm gear (not shown) screws into the threaded worm gear receptacle of travelling support member 20. The other end of this worm gear is fixed to the center of a second metering disc 44, which has a plurality of teeth 46 equidistantly spaced around the circumference thereof. A portion of the worm gear near to the end fixed to second disc 44 is rotatably supported in a bearing (not shown) which is attached to machine base 22. Rotation of second disc 44 rotates the worm gear inside the tongue portion of travelling support member 20, and accordingly, travelling support member 20 is translated along the upper surface of machine base 22 toward or away from second disc 44, depending upon whether the worm gear is rotated clockwise or counter-clockwise. Arm support member 18 and punch 12 are translated along with travelling support member 20 to and fro relative to blank cylinder 26, which is rotatably mounted between the centers.
In operation, the operator determines the distance along the longitudinal axis of cylinder 26 that punch 12 must travel relative to cylinder 26 in order to be positioned over the blank portion of cylinder 26 that is to receive the next mark of the punch. The spacing between each tooth 46 of second disc 44 corresponds to a precise longitudinal distance of travel along the longitudinal axis of cylinder 26 by travelling support member 20 relative to cylinder 26. The operator raises a second handle 48 which is attached to a second shifting arm 50. A ratchet pawl is attached to the side of second shifting arm 50 that is out of view in FIG. 1. The operator lifts second handle 48 until the ratchet pawl ratchets past the desired number of teeth 46. Then, the operator moves the handle back down until second shifting arm 50 touches a lower arm stop, such as a bolt and nut combination 52. A second arm gauge 53 is fixed to machine base 22 alongside second shifting arm 50. Another nut and bolt combination 54 can be mounted on second arm gauge 53 to act as an upper stop for arm 50.
Accordingly, the operator of conventional apparatus 10 is able to form a punched pattern of predetermined design on the surface of cylinder 26 by manipulating punch 12, first handle 36, and second handle 48 in a predetermined sequence calling for shifting a predetermined number of teeth 32 and 46 along respective discs 30 and 44.
Forming a single pattern on a single blank cylinder using a conventional apparatus is a very time consuming and repetitive task requiring painstaking care of the operator to strike the cylinder with punch 12 the desired number of times and to shift shifting arms 34 and 50 in the required sequence. Operation of the conventional apparatus requires a skilled individual with the judgment to set the punch to strike the correct portion of the blank cylinder and to strike it with the proper force. In addition, the operator must possess the patience and care needed to devote many hours to the repetitive task of operating the conventional apparatus. Even the simplest of patterns formed on a blank cylinder can require several weeks of work by a single operator using the conventional apparatus.
Accordingly, patterning a blank cylinder using a conventional apparatus is a very expensive manufacturing operation. This is primarily due to the labor expense of the operator of the conventional apparatus. Successful operators are rare individuals due to the great care, precision and detail that are characteristic of the work required of the operator of the conventional apparatus.